The shades of each mark represent a win, podium, or a top 10 finish, and it catagorizes every driver that ever participated in an F1 race. The datapoints are name, age, finish, and date. If you highlight over each mark, it will show what event it was.

It would be neat to sort it by number of wins, championships, etc, but it appears that it's locked to the timeline. Unfortunately, you can only sort the information three ways.